The present invention relates to artificial ground coverings and, more particularly, to an artificial pine needle for use as a ground cover.
Pine needles are used in gardening and landscape design and maintenance as a ground cover to protect vegetation from the elements, suppress weed growth, provide moisture retention, and provide an evaporation barrier. Further, pine needles are valued for their fresh reddish-brown or yellowish-brown colors during the spring and fall. However, the use of pine needles is limited in availability because of the geography where pine trees providing such pine needles grow and the costs of transporting pine needles.
In addition to the pure economics of using of natural pine needles, other factors influence the desirability of natural pine needles. Foremost, natural pine needles deteriorate rapidly as a result of aging, ultraviolet exposure, and weather. Within 60 to 90 days, natural pine straw begins to lose its color and appearance of freshness and becomes drab and unattractive. With the loss of color, natural pine needles also lose their natural fragrance that is so pleasing. Further, as the straw ages and becomes mildewed and rotten it becomes more difficult to fluff the straw and clean out any leaves and twigs. Alas, natural pine straw must be replaced frequently, every few months, to maintain its fresh appearance and odor.
Besides the material cost for the straw, which is labor intensive to gather in the first instance, applying straw to a bed of vegetation is labor intensive and costly. Often as a cost cutting measure, the old straw is left on the ground, and new straw is applied over the old. However, the presence of deteriorating old straw has disadvantages in that the old straw retains excess moisture keeping that moisture from the soil. Thus, the old straw may impair the proper root growth of the vegetation causing the roots to seek the moisture locked in the deteriorated straw.
The disadvantages of natural straw shown above can be overcome by the purchase of fresh straw and its labor intensive application. However, there are still further disadvantages of natural straw. For instance, natural straw is raked and gathered from the ground such that it contains contaminants such as sticks, leaves, and twigs. Natural straw may also carry molds, disease, bugs and insects, or weed and grass seeds that may be a nuisance to plants or the home. Finally, natural pine straw is very flammable and may cause the rapid spread of fire, rendering straw a fire hazard.
As an alternative to natural straw, synthetic straw has been considered. Synthetic straw is advantageous in that it is sterile when applied without contaminants or disease. After application as a ground cover, leaves and twigs may be removed from the synthetic straw by fluffing. Fluffing is the process of lifting the straw up and shaking it out again, whereby, the leaves and twigs in the straw become hidden and can decompose. The fluffing process is difficult with mildewed or rotten natural pine straw. Whereas, synthetic straw does not rot and decomposes very slowly with exposure to the ultraviolet rays from sunlight.
Therefore, it can be seen that a need exists for an alternative to natural pine straw for use as a ground cover and that a synthetic pine straw would be desirable. Several attempts have been made to provide synthetic ground coverings, but these ground coverings have been too shiny, hard, irregularly shaped, or generally artificial in appearance. U.S. Pat. No. 4,855,166 to Allison provides an artificial pine needle that includes a plurality of strands attached together to emulate the appearance of a natural pine needle. However, the process of binding the strands is expensive and the artificial attachment of the strands detracts from the pine needle""s natural appearance.
Therefore, it is a primary object of the present invention to provide an artificial pine needle having similar characteristics to a natural pine needle.
It is another object of the present invention to provide an artificial pine needle that may be produced easily and inexpensively.
It is another object of the present invention to provide an artificial pine needle that will promote the proper drainage of water into the soil beneath bedded plants.
It is another object of the present invention to provide an artificial pine needle that will exceed the life of natural pine needles as a ground cover.
It is still a further object of the present invention to provide an artificial pine needle that is free of contaminants and that may assist in the application of fertilizer and pesticides to bedded plants.
It is yet a further object of the present invention to provide an artificial pine needle which provides a pleasant odor.
The present invention relates to synthetic artificial pine straw needles comprised of a monofilament strand of synthetic material. The monofilament strand is molded and extruded through a die during manufacture such that the artificial pine straw needle has a substantially C-shaped or U-shaped cross sectional shape, providing an artificial pine straw closely resembling the appearance of natural pine needles. Further, the C-shaped or U-shaped cross section provide maximum surface area on the artificial pine needle for providing ground cover, while the material usage in the construction of the artificial pine needle is reduced. The C-shaped or U-shaped cross section gives substantial costs savings on raw materials used in manufacture compared to an artificial pine needle having a circular or cube shaped cross section.
The monofilament strand of the present invention primarily comprises a polyolefin resin which makes up 80 percent or more of the weight of the strand. Because the structural properties of an artificial pine needle are not critical, the monofilament may comprise a polyolefin consisting of recycled polypropylene homopolymer. In particular, the artificial pine needle of the invention may consist of 80 percent or more by total weight of recycled polypropylene blended with 20 or less percent by total weight of an additive blend that imparts desirable characteristics of color, scent, and durability to the product.
In general, the additive may include a ultraviolet inhibitor to enhance the life of the artificial pine needle and pigment and calcium carbonate to provide suitable color and limited luster. The inventor has found that an additive providing to the to the total weight of the blend about 0.1 to 0.2 percent by weight of ultraviolet inhibitor, 0.15 percent by weight of iron oxide/carbon pigments, and about 15 to 20 percent by weight of calcium carbonate in a polyethylene carrier resin provides excellent quality artificial pine straw with appropriate color and luster. The ultraviolet inhibitor permits the artificial pine needles to last for two years or more before needing to be replaced.
In addition to the standard artificial pine needle, several additional additives may be included to impart desirable characteristics. For instance, a citronella concentrate oil may be added to the additive such that the artificial pine needle will have a pleasant scent and ward off mosquitoes. Likewise, a pine scent or fresh flower scent could be added to the additive blend. A fragrance or the like embodied within a monofilament strand like that in the present invention will be released in proportion to the external surface area of the monofilament strand. The C-shaped or U-shaped artificial pine needle maximizes the available external surface area. Therefore, the invention provides advantages in the release of fragrances or other chemicals that are embodied within the artificial pine needle.
The inward surface area of the C-shaped or U-shaped artificial pine needle provides an excellent surface for carrying additional additives that may be applied on the exterior of the pine needle. The inward surface is ideal in that it is not as visible and additives thereon will not significantly effect the appearance of the artificial ground cover. Also, the inward surface of the C-shaped cross section provides a cavity for application of ample amounts of any such additive. As a result, the inward exterior surface of the artificial pine needle is well suited for coating of the surface with a fertilizer or pesticide. Therefore, in one process of manufacture a ground covering may be provided that also acts as a means for transmitting long-acting fertilizers or pesticides to bedding plants.
The process of fluffing artificial pine needles that have been set out as ground cover lengthens the expected life of the artificial straw. As described above, ultraviolet inhibitors are added to extend the life of the artificial straw to exceed two years, but with fluffing and shade the actual life of the artificial straw may be considerably longer. Over time, some fading of the artificial straw will occur. When the artificial pine needles disclosed herein are removed as a ground covering, the artificial needles may be thrown away with other yard trash and disposed of without harm to the environment. Further, the residual decomposed material left in the beds will gradually reduce to the base materials the artificial needles are comprised of which are environmentally harmless.
The present invention includes method of manufacture of artificial pine needles having a substantially C-shaped or U-shaped cross section. The method of manufacture comprises the steps of blending a resin and additives in which the resin is a polyolefin substance such as recycled polypropylene. The additive will preferably consist of a polyethylene carrier, pigment, calcium carbonate, and an ultraviolet inhibitor. The blend is extruded into monofilaments through a C-shaped or U-shaped die.